Breeding

Every puppy is precious, and the best way to help them be healthy is to enlist expert help with conception, supporting the pregnancy and throughout the birth, writes Dr Grant Poolman.

Every breeder wants a litter with a good number of healthy pups, whether they are breeding to maintain a valuable genetic line or supply healthy pups to new homes.

More and more breeders are turning to their veterinarian for assistance with breeding, firstly to get their bitch pregnant, then to maintain the pregnancy and finally to deliver the pups.

Pregnancy-ready

The single greatest advance in achieving pregnancy for breeding bitches has been the regular use of progesterone assessments.

Until recently, bitches were assessed as ready to mate by a variety of indirect methods. These included counting the days she had been in season and observing characteristics of the vaginal discharge or the reactions of male dogs to her.

All of these gave a guide, but did not tell exactly what was happening inside the bitch’s reproductive tract. Progesterone tests taken regularly through the heat period give an accurate assessment of the ideal time to mate.

Artificial insemination

Knowing the ideal time to mate is valuable irrespective of the mating method to be undertaken. These methods now include natural mating and several forms of artificial insemination (AI), using fresh, chilled or frozen semen.

AI can be useful if for any reason the male and female are not compatible for natural mating.

When AI with fresh semen is used, the semen is collected by a veterinarian when both the male and female dogs are present. An advantage of AI using this semen is that the semen can be assessed before implantation. This is particularly valuable when using a young, untried male or an older but fading male.

There is recent evidence showing the value of using fresh semen surgically injected directly into the uterus. This method is showing particular promise in bitches with a poor breeding history.

It is also proving useful when the semen collected from the male is of low numbers or motility. In these cases, semen inseminated intravaginally may not reach the uterus, so placing the semen directly into the uterus increases the likelihood of achieving a pregnancy.

Chilled semen

New advances in technology have improved the success of transporting chilled semen around Australia. Until recently, chilled semen could be expected to last about 72 hours, which meant racing to airports to send and receive shipments.

Use of this chilled semen also required very careful and difficult assessments of progesterone tests, as the veterinarian was usually trying to assess the progesterone level at least a day in advance to allow time for the semen to arrive.

Fortunately, there is now available a transport medium that will preserve 90 per cent of the motility of spermatozoa for ten days at refrigerated temperature. This means that semen can be collected, chilled and packed in the chiller box, then sent almost anywhere in Australia by overnight express from the nearest post office.

The success rate when using chilled semen is very similar to that achieved when fresh semen is implanted immediately after collection.

Frozen semen

With the introduction of the Camelot freezing method, which uses the special Camelot formulated medium to produce pellets, freezing semen made a quantum leap forward. The veterinarians accredited to use this system are achieving impressive results: approximately 94 per cent pregnancy rate for Greyhounds and 84 per cent for other breeds.

The difference between the two is largely due to the accreditation system of the Greyhound Racing Authority, which insists stud dogs must have the quality of their semen assessed and accredited before being used for AI.

Not only is frozen semen a useful tool for sending semen long distances, including internationally, it is also excellent insurance for high-quality genes. Semen can be collected and frozen before the fertility begins to wane, which can happen from six years of age and sometimes without the breeder being aware of any changes, as a male dog is capable of producing puppies by natural service even though its semen may be of insufficient quality to freeze.

Keeping her pregnant

Recently, we have seen some bitches become pregnant from AI, but resorb the foetuses – in the past it would have been assumed that they didn’t become pregnant at all.

Again, progesterone testing is proving invaluable in these situations. An ultrasound can be used to diagnose early pregnancy, and progesterone assessment can then be used to determine whether the bitch has adequate progesterone levels to maintain the pregnancy.

If the progesterone level in the blood of the bitch falls after a positive ultrasound has been achieved, supplementation with oral micronised progesterone will often save the litter.

Micronised progesterone is progesterone that has been broken down into very fine particles, and is favoured because its levels can be monitored in the body and the dose adjusted to the correct level.

This is important because too low a progesterone level can result in loss of the pregnancy and too high may cause foetal abnormalities. Injectable progesterone is not easily monitored and cannot be readily adjusted.

Delivering the pups

The first and most important information a breeder expecting pups can have is the schedule. Knowing what to expect and when allows breeders to plan and provide the best care for mother and pups. Again, this is where a veterinarian can help if progesterone levels were assessed at mating time.

If the progesterone test is not available, careful breeders may record a drop in the bitch’s body temperature as whelping time approaches and she begins to ‘nest’.

When and how can a veterinarian assist at this time? Clearly, if the bitch is having contractions and not producing puppies then assistance is required. However, there can be more subtle indications of trouble and, again, the progesterone assay and the ultrasound machine can provide valuable information.

Progesterone is often referred to as the hormone of pregnancy. This is because it rises at the beginning of pregnancy and falls sharply just before the pups are due. A fall in progesterone levels in the blood of the bitch without her starting to whelp can be a danger sign and may indicate that she is unable to contract and expel the pups.

A veterinarian may also detect a fall in the heart rate of the unborn pups when using an ultrasound machine. Pups with falling heart rates are stressed and unfortunately this indicates that a caesarian delivery may be required.

After the puppies are born the most important thing for the breeder to monitor is that the puppies are kept warm. Cold pups do not eat and, even if tube fed, they do not have the ability to absorb the food. Keep puppies nice and warm and other natural activities should follow.

METHODS OF AI

Intravaginal insemination

This method is the most straightforward. The semen is collected from the dog and deposited in the bitch’s vagina either fresh or chilled, from where it travels to the uterus and, hopefully, fertilises the ova, resulting in pregnancy.

Surgical insemination

In this method, fresh, chilled or frozen semen is injected directly into the uterus. This is a surgical procedure, and general anaesthesia is required.

Trans-cervical insemination

In this method, semen is deposited directly in the uterus by a vet using an endoscope or a catheter. This method is becoming more reliable and generally does not require sedation, so carries less risk.